Method of concentrating oil shales



Patented Get. 7, 1924.

SAMUEL H. DOLBEAR, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR F ONE-HALF TOEDWIN LETTS OLIVER, OF SAN FRANCISCO, CALIFORNIA.

METHOD OF CONCENTRATING OIL SHALES.

No Drawing}.

To all whom it ma cmwem:

Be it known that SAMUEL H. DOLBEAR, a citizen of the United States,residing at San Francisco, in the county of San Francisco and State ofCaliforma, have invented new and useful Improvements in Methods ofConcentrating Oil Shales, of which the followingis a specification. 1

This invention relates to a method of treatingoil shales and has for itsobject to separate the valuable organic compounds in the shale from thewaste or gangue which produces no oil. I I I Usually the oil does notexist as such in the shale and when resent is found in very minutequantities but is produced by the destructive .disti ation. of complexorganic compounds in the shale. Destructive distillation, that is,heating in the absence of air, decomposes this organic matter and yieldshydrocarbon oils and' permanent gases.

In carrying ou-t'my object I'concentrate the valuable organic compoundspresent in the oil shale by subjecting a pulp of. oil

shale to flotation.

In flotation as heretofore vpracticed, advantage .is taken of theselective preference .of oil for the metallic and certain metalloidparticles such as' graphite, present in the ore. I have discovered thatoil and some other substances have a selective affinit for certainorganic substances present in oil shales and that if the shales aresuitable. quantity of oil or other selective reagents be present, andthe mixture aerated, bubbles will be formed to which the valuable.organic compounds attach themselves and are brought to 'the surface bthe bubbles and are retained .in the frot formed at the surface. Thefroth may then be readily separated from the liquid. All organicsubstances do not exhibit this characteristic of selective preference tooil, and it is believed that the cohesion of the two in the presentinvention is due to the natural preference of certain oily liquids forrelated hydrocarbon solids. At present there are no shale oil operationsin this country that have reached commercial production, although thereis a great deal of activity, particularly in the States of Colorado,Utah and Montana where there are large and easily accessible deposits offinely ground and mixed with water and a.

termined b Application filed November 11, 1920. Serial No. 423,317.

rich shale. The chief reason for the failure 'to produce oilcommercially from shale in this country has been the expense inconnection with destructively distilling the shale. There is present inthe shale a lar e quantity of waste or gangue which yiel s no oil. Byseparating this waste or gangue before the destructive distillingoperation is carried out a reatsaving is effected in time, labor andFuel Y My invention may be practiced with many different kinds ofapparatus and any of the well known machines used in the flotation ofmetalliferous ores may be used as desired. The steps contemplated are:grinding of the shale into a pulverulent state; mixing this'powderedmaterial with water; adding a small quantity in cases where there is aninsuflicient quantity of free oil in the shale to effect a-flotation,and aerating the pulp or mixture by introducing air through it to createa froth, which froth will rise to the surface car ing with it thevaluable organic compoun s present in the shale while the earthysubstances present, such as siliciou's material, gypsum and otherinorganic compounds sink. Thereafter the valuable portion may be skimmedoff and destructively distilled in the usual way to extract the oil andother valuable ingredients therefrom. In practicing this process it isnecessary to have present a small uantity of oil or other flotativereagent in t e pulp, the character and quantity of which must bedepreliminary tests. If, however,;the s ales are found to contain freeoil in such quantity as to act as a flotative agent then no oil need. beadded. In using the term oil shales hereinI do not refer to shales .inwhich a substantial amount of free oil is resent, such for instance assome of the sh es found in California. In the concentration of someshales it may be desirable to add an electrolyte, such as sulfuric acid,especially where the earthly material has a tendency to slime or becomecolloidal on grinding; The amount and character of such electrolyte mustbe determined by prelimina tests.

Having thus describe my invention, what of oil to the water I claim anddesire to secure by Letters shale into e liquid pulp. suhjecicing thepulp io froth flotation, sepei'efcing ihe isesu newt froth from theremainder and clestruclaively clistiilinw only those particles when oilwith the from. I

2: A method of recovering oil from shale which consists in reducing theshale to &

'pulverulent Sim, mixing lhe ame with Water warming the mixture soformed to piofluce a Eioioh on the surface, separating the froth fromthe *remeinder encl destructively distilling only those particles taken05 with the froth.

3. A method of recovering oil from shale which consists iii reducing theshale to o pulverulemfi stole, "forming a, pulp thereof by the adlitionof Weierenoi e til-y of flotetive reagent eeieiing so as to produce afroth on the em .2102 9)., separating the resultant froth from 'Tahemeinder mid destruolhively oiieiilling 0 these particles token oil? withthe fret? & A method of recovering oil from which consists in refiuciiogthe shele icein pulverulent state, forming e pulp cheieof by fitheaddition of Walter and an electrolyte, aerating the pulp so as toproduce froth on the surface, separating the resultant froth from theremainder encl desiruciively distilling only those particles taken offWilli 1 the froth.

